Resin sheets exhibiting enhanced adhesion to inorganic surfaces

ABSTRACT

Resin layers and interlayers exhibiting enhanced adhesion to inorganic surfaces, such as glass, are provided. In some cases, the layers and interlayers may comprise at least one adhesion stabilizing agent for improving adhesion to various surfaces, even in the presence of moisture. Such layers and interlayers may be useful, for example, in multiple layer panels, such as, for example, safety glass used in automotive and architectural applications.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No.14/887,907, filed Oct. 20, 2015, currently pending, which is acontinuation-in-part of U.S. application Ser. No. 14/562,809, filed Dec.8, 2014, now U.S. Pat. No. 9,382,355, the entire disclosure of which isincorporated by reference herein.

BACKGROUND

1. Field of the Invention

This disclosure relates to polymer resins and, in particular, toadhesion stabilized polymer sheets suitable for use in polymerinterlayers, including those utilized in multiple layer panels.

2. Description of Related Art

Polyvinyl butyral (PVB) is often used in the manufacture of polymersheets that can be used as interlayers in multiple layer panels,including, for example, light-transmitting laminates such as safetyglass. PVB is also used in photovoltaic solar panels to encapsulate thepanels which are used to generate electricity for commercial andresidential applications.

The term “safety glass” generally refers to a transparent laminate thatincludes at least one polymer sheet, or interlayer, disposed between tworigid substrates, such as, for example, two sheets of glass. Safetyglass is often used as a transparent barrier in architectural andautomotive applications, and one of its primary functions is to absorbenergy resulting from impact and to prevent objects from passing throughthe laminate. Additionally, even when the applied force is sufficient tobreak the glass, the polymeric interlayer helps keep the glass bonded tothe laminate, which prevents dispersion of sharp glass shards, therebyminimizing injury and damage to people or objects in the vicinity of theglass. Safety glass may also provide other benefits, such as a reductionin ultraviolet (UV) and/or infrared (IR) radiation, and it may alsoenhance the aesthetic appearance of window openings through addition ofcolor, texture, and the like. Additionally, safety glass with desirablesound insulation properties has also been produced, which results inquieter internal spaces.

The ability of PVB to remain adhered to glass and other inorganicsurfaces in a multiple layer panel depends, in part, on the environmentin which the panel is utilized during service. In particular,PVB-containing multiple layer panels used in hot and humid environmentsare susceptible to ingress of moisture, particularly at the edges of thelaminate, which may lead to edge delamination. Such delamination reducesthe functionality of the panel by adversely impacting its mechanical,optical, and even acoustic performance.

Thus, a need exists for a poly(vinyl acetal) sheet that exhibitsenhanced surface adhesion and that can be used in multiple layer panelsutilized under a wide range of service conditions, including hot andhumid environments, for extended periods of time with steady adhesion.Advantageously, such a sheet could be prepared using existing processingequipment and with minimal additional cost or process steps.

SUMMARY

One embodiment of the present invention concerns a method of making ortreating an interlayer. The method comprises applying a coating materialto at least a portion of at least one surface of an ionomeric resinsheet to thereby provide a surface-treated ionomeric resin sheet. Thecoating material comprises at least one silanol-containing adhesionstabilizing agent or precursor thereto.

Another embodiment of the present invention concerns a method of makinga multiple layer panel. The method comprises applying a coating materialto at least a portion of at least one surface of an ionomeric resinsheet to thereby provide a surface-treated ionomeric resin sheetcomprising one or more surface-treated locations. The coating materialcomprises at least one silanol-containing adhesion stabilizing agent orprecursor thereto. The method also comprises assembling thesurface-treated ionomeric resin sheet between a pair of rigid substratesto form a construct. The surface-treated ionomeric resin is positionedbetween the pair of rigid substrates such that at least a portion ofsaid surface-treated locations are in contact with one of said rigidsubstrates. The method also comprises laminating said construct to formsaid multiple layer panel.

Yet another embodiment of the present invention concerns an interlayersheet comprising an ionomeric resin and at least one silanol-containingadhesion stabilizing agent. The sheet comprises one or moresurface-treated locations exhibiting a silanol concentration gradientcharacterized by a surface concentration of elemental silicon that isgreater than a mid-thickness concentration of elemental silicon.

DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention are described in detailbelow with reference to the attached drawing Figures, wherein

FIG. 1 is a graphical representation of how R_(z) is measured inaccordance with DIN ES ISO-4287 of the International Organization forStandardization and ASME B46.1 of the American Society of MechanicalEngineers;

FIG. 2 is a schematic depiction of a cross-section of a surface-treatedpolymer sheet according to various embodiments of the present invention,particularly illustrating the relative positions of a surface locationand a mid-thickness location;

FIG. 3 is a schematic perspective view of a surface-treated polymersheet according to various embodiments of the present invention,particularly illustrating the perimeter and interior regions of thesheet;

FIG. 4 is a graphical depiction of the peel adhesion values for severalpoly(vinyl n-butyral) resin samples treated with hydrolyzed silane sprayas described in Example 4; and

FIG. 5 is a graphical depiction of the peel adhesion values for severalpoly(vinyl n-butyral) resin samples treated with an unhydrolyzed silanespray as described in Example 4.

DETAILED DESCRIPTION

The present invention relates to polymer layers and interlayers havingimproved adhesion to glass, metal, and other inorganic materials. Invarious embodiments, the layers and interlayers described herein caninclude a polymer sheet and at least one adhesion stabilizing agentpresent on at least a portion of the surface of the polymer sheet. Priorto bonding to the surface, the resin layer or interlayer may be treatedwith a coating composition that includes an adhesion stabilizing agentand, as a result, the treated layer may exhibit enhanced adhesionproperties as compared to similar untreated sheets, particularly afterprolonged exposure to hot and humid environmental conditions.Consequently, resin layers and interlayers according to embodiments ofthe present invention can be used in multiple layer panels that areemployed in a wide variety of end uses, including automotive andarchitectural applications.

As used herein, the terms “polymer resin layer” and “resin layer” referto one or more polymer resins, optionally combined with one or moreplasticizers, that have been formed into a polymeric sheet. Resin layersmay include one or more additional additives. As used herein, the term“interlayer” refers to a single or multiple layer polymer sheet that maybe suitable for use with at least one rigid substrate to form a multiplelayer panel. The terms “single-sheet” and “monolithic” interlayer referto interlayers formed of one single sheet, while the terms “multiplelayer” and “multilayer” interlayer refer to interlayers having two ormore sheets that are coextruded, laminated, or otherwise coupled to oneanother.

According to various embodiments of the present invention, resin layersand interlayers may include at least one polymer sheet and at least oneadhesion stabilizing agent. The adhesion stabilizing agent can be anycompound or material that facilitates enhanced or stabilized adhesionbetween the surface of the polymer sheet and another inorganic surface,such as, for example, a glass surface. In some embodiments, theinorganic surface can be part of an inorganic substrate, such as glassor metal, while, in other embodiments, the inorganic surface may be partof an organic substrate treated with an inorganic coating, such as, forexample, a metal oxide coating. Rather than be incorporated into thepolymer resin layer or applied to the inorganic surface itself, theadhesion stabilizing agent according to embodiments of the presentinvention may be present on at least a portion of the surface of thepolymer sheet prior to adhering the polymer sheet to the inorganicsurface.

In some embodiments, the adhesion stabilizing agent can be added to thesurface of a polymer sheet by applying a coating material to at least aportion of the sheet surface. The coating material can include theadhesion stabilizing agent, or a precursor thereto, and at least onecarrier liquid. When an adhesion stabilizing agent precursor is presentin the coating material, at least a portion of the precursor can beconverted to an adhesion stabilizing agent upon application to thesheet. Alternatively, at least a portion of the precursor may beconverted to the adhesion stabilizing agent within the coating material,or the coating material may include the adhesion stabilizing agentitself.

The adhesion stabilizing agent can comprise an organic adhesionstabilizing agent, such as, for example, a silanol compound. When theadhesion stabilizing agent present on the surface of the sheet comprisesa silanol, the coating material applied to the surface of the polymersheet may include the silanol, or it may include one or moreunhydrolyzed silicon-containing compounds that can be converted tosilanol upon application of the coating material to the sheet. Examplesof suitable silicon-containing compounds that are readily convertibleinto silanol containing compounds can include organic alkoxysilanesincluding monoalkoxysilanes, dialkoxysilanes, and trialkoxysilanes. Insome embodiments, the silicon-containing compound may be atrialkoxysilane such as, for example, a trimethoxysilane or atriethoxysilane. Examples of suitable trialkoxysilanes can include, butare not limited to, γ-glycidoxypropyltrimethoxysilane,aminopropyltriethyoxysilane, aminoethylaminopropyltrimethoxysilane, andcombinations thereof. When the silicon-containing compound comprises asilanol, it may comprise the hydrolyzed form of one or more of thesilicon-containing compound listed above.

The coating material may further include at least one carrier liquidcapable of dissolving or dispersing the adhesion stabilizing agent, orprecursor thereto, and for facilitating application of the adhesionstabilizing agent or precursor to the surface of the polymer sheet. Insome embodiments, the carrier liquid can comprise an aqueous carrierthat can include, or be, water, while, in some embodiments, the carrierliquid can be an organic carrier that comprises one or more organicsolvents, such as, for example, methanol. In some embodiments, thecarrier liquid can comprise a mixture of water and one or more organicsolvents, such as, for example, methanol. Depending on the type andamount of the adhesion stabilizing agent present, the coating materialcan have a pH of at least about 1, at least about 1.5, at least about 2,at least about 2.5, at least about 3, at least about 3.5, at least about4, at least about 4.5 and/or not more than about 7, not more than about6.5, not more than about 6, not more than about 5.5, or not more thanabout 5, or a pH in the range of from 1 to about 7, about 1.5 to about5.5, or about 2 to about 5. In some embodiments, the coating materialcan have a pH of at least about 8, at least about 8.5, at least about 9,at least about 9.5 and/or not more than about 14, not more than about13, not more than about 12, not more than about 11, or in the range offrom about 8 to about 14, about 8.5 to about 13, about 9 to about 12, orabout 9.5 to about 11.

The adhesion stabilizing agent, or its precursor, may be present in thecoating material in any concentration and, in some embodiments, may bepresent in an amount of at least about 0.004, at least about 0.005, atleast about 0.0075, at least about 0.010, at least about 0.025, at leastabout 0.050, at least about 0.10, at least about 0.25, at least about0.75, at least about 1, at least about 1.25, at least about 1.5, atleast about 2, at least about 2.5, at least about 5 and/or not more thanabout 25, not more than about 20, not more than about 15, not more thanabout 12, not more than about 10, not more than about 7.5, not more thanabout 5, not more than about 2.5, not more than about 2, or not morethan about 1.5 weight percent, based on the total weight of the coatingmaterial, or an amount in the range of from about 0.004 to about 25,about 0.0075 to about 20, about 0.010 to about 15, or about 0.25 toabout 7.5 weight percent, based on the total weight of the coatingmaterial.

The coating material can be applied to at least one surface of thepolymer sheet according to any suitable method. In some embodiments, atleast a portion of the sheet may be dip coated, such that all or aportion of the sheet is submerged in the coating material. In otherembodiments, the coating material may be applied to at least a portionof the polymer resin surface by spray coating. Other suitable coatingmethods, including, for example, gravure coating or inkjet printing, mayalso be used. When the sheet is dip coated, the dip time can be at leastabout 0.5 seconds, at least about 30 seconds, at least about 1, at leastabout 2, at least about 5, at least about 10, at least about 30, atleast about 60 minutes and/or not more than about 90, not more thanabout 60, not more than about 30, not more than about 15 minutes, or notmore than about 10 minutes, or in the range of from about 0.5 seconds toabout 90 minutes, about 30 seconds to about 30 minutes, or about 1minute to about 10 minutes.

Once the coating material has been applied to the surface of the polymersheet, it may be allowed to dry for a period of at least about 30seconds, at least about 1 minute, at least about 2, at least about 3, atleast about 5, at least about 10, at least about 15, at least about 30minutes and/or not more than about 90, not more than about 60, not morethan about 45, not more than about 30, not more than about 15, not morethan about 10, not more than about 5 minutes, or for a period of time inthe range of from 30 seconds to 90 minuted, from 1 minute to 60 minutes,or from 2 minutes to 15 minutes. Such drying can be performed underambient conditions, in a room-temperature desiccator, or alow-temperature oven, as needed. Once dried, the surface-treated polymersheet can be used in various applications, as described below.

In some embodiments, the polymer sheet can have a surface roughness,measured as R_(z), of at least about 5, at least about 10, at leastabout, at least about 15, at least about 20, at least about 25, at leastabout 30, at least about 35 microns (μm) and/or not more than about 150,not more than about 100, not more than about 80, not more than about 75μm, or it can have a surface roughness in the range of from about 5 toabout 150, about 10 to about 100, or about 25 to about 75 μm. Thesurface roughness, or R_(z), of the surface of the polymer sheet ismeasured by a 10-point average roughness in accordance with DIN ESISO-4287 of the International Organization for Standardization and ASMEB46.1 of the American Society of Mechanical Engineers. In general, underthese scales, R_(z) is calculated as the arithmetic mean value of thesingle roughness depths R_(zi) (i.e., the vertical distance between thehighest peak and the deepest valley within a sampling length) ofconsecutive sampling lengths:

$R_{z} = {\frac{1}{N} \times \left( {R_{z\; 1} + R_{z\; 2} + \ldots + R_{zn}} \right)}$

A graphical depiction of the calculation of an R_(z) value in accordancewith DIN ES ISO-4287 of the International Organization forStandardization and ASME B46.1 of the American Society of MechanicalEngineers is provided in FIG. 1. In the calculation, the length of eachtrace (I_(R)) is 17.5 millimeters composed of seven sequential samplelengths (I_(c)) of 2.5 millimeters each. The measuring length (I_(m)) is12.5 millimeters and is composed of five sequential sample lengths(I_(c)), obtained by eliminating the first and last sections of eachtrace.

In various embodiments of the present invention, at least a portion ofthe surface of the coated polymer sheet can comprise one or morelocations that exhibit a concentration gradient of the adhesionstabilizing agent between the surface of the sheet and a mid-thicknesslocation of the sheet. In particular, with reference to FIG. 2, theconcentration gradient of the adhesion stabilizing agent may becharacterized by a higher concentration of the adhesion stabilizingagent, or marker thereof, present at the surface 12 of treated sheet 10than at a mid-thickness location 14 of sheet 10. As used herein, theterm “mid-thickness location” refers to a location spaced an equaldistance from the upper and lower surfaces of a sheet that lies along aline drawn through the surface-treated location 12 that is perpendicularto both the upper and lower surfaces of the sheet, as shown, forexample, as dashed line 50 in FIG. 2.

In some embodiments, depending on the type and amount of adhesionstabilizing agent present on the surface of the polymer layer, theconcentration gradient may be characterized by the difference inconcentration of the adhesion stabilizing agent itself through thethickness of the sheet. In some embodiments, when, for example, theadhesion stabilizing agent is present on the polymer surface inrelatively low amounts, the concentration gradient between thesurface-treated and mid-thickness locations may be measured by detectionof one or more atomic markers, such as, for example, silicon when theadhesion stabilizing agent comprises a silanol. According to variousembodiments, the sheet may include one or more surface-treated locationsthat exhibit a silanol concentration gradient characterized by a surfaceconcentration of elemental silicon that is greater than a mid-thicknessconcentration of elemental silicon.

The surface concentration of the adhesion stabilizing agent, or markerthereof, can be at least about at least about 50, at least about 100, atleast about 200, at least about 400, at least about 1,000, at leastabout 2,000 percent higher than the mid-thickness concentration of theadhesion stabilizing agent, or marker thereof. The molar ratio of thesurface concentration to the mid-thickness concentration can be at leastabout 10:1, at least about at least about 20:1, at least about 100:1, atleast about 250:1, at least about 500:1, at least about 1000:1, at leastabout 5000:1, at least about 10,000:1 and/or not more than about100,000:1, not more than about not more than about 50,000:1, not morethan about 25,000:1, not more than about 15,000:1, not more than about10,000:1, or in the range of from about 10:1 to about 100,000:1, about500:1 to about 50,000:1, about 10,000:1 to about 50,000:1. In variousembodiments, at least about 50, at least about 60, at least about 70, atleast about 80, at least about 90, or at least about 95% of the totalamount of the adhesion stabilizing agent can be present at or near thesurface.

In some embodiments, the amount of adhesion stabilizing agent present atthe surface of the polymer sheet can be characterized using X-rayphotoelectron spectroscopy (XPS). The XPS method used to obtain numericvalues for the amount of adhesion stabilizing agent described herein wasperformed using an AXIS Nova spectrometer (commercially available fromKratos Analytics Ltd, Manchester, UK) with CasaXPS software version2.3.17. The quantification was based on a wide scan survey spectra andwas reported in relative atomic mole percent. Unless otherwisespecified, all survey spectra obtained during the analysis werecollected with an Al K_(α) monochromatic source operating at 150 W (15kV, 10 mA) with a pass energy of 80 eV. The acceptance angle was +/−15°in spectroscopy mode, with a take-off angle of 90° and an analysis areaof 700×300 μm. The charge neutralization was on and the chargecorrection was C 1s 284.8 eV. The narrow scan (high resolution) spectrawere collected for elements of interest, including carbon, oxygen, andsilicon, for peak fitting to elucidate oxidation states/chemicalenvironments. These narrow spectra were collected using the sameparameters described above for the wide scan with the exception of passenergy. Unless otherwise specified, the narrow scan spectra werecollected using 20 eV pass energy.

According to some embodiments, the amount of silicon, or other adhesionstabilizing agent or marker thereof, present at the surface of thepolymer sheet may be at least about 0.10, at least about 0.30, at leastabout 0.50, at least about 0.75 and/or not more than about 15, not morethan about 10, not more than about 5, not more than about 3, not morethan about 1.5, not more than about 1.25 atomic percent, measured by theXPS method described above. The amount of silicon, or other adhesionstabilizing agent or marker thereof, present at the surface of thepolymer sheet can be in the range of from about 0.10 to about 15, about0.3 to about 3, about 0.50 to about 1.5 atomic percent (at %), measuredas described above.

The surface-treated locations of the polymer sheet can be present onsubstantially all, or a portion, of the surface of the polymer sheet. Insome embodiments, only a portion of the surface of the sheet can betreated, such that, for example, at least about 5, at least about 10, atleast about 15, at least about 20, at least about 30, or at least about40 percent of the surface of the sheet remains untreated, while, inother embodiments, nearly all of the surface of the sheet may betreated. In some embodiments, at least about 5, at least about 10, atleast about 15, at least about 20, at least about 30, at least about 40,at least about 50, at least about 60, at least about 70, at least about80, or at least about 90 percent of the total surface area of the sheetmay be treated with the adhesion stabilizing agent as described above.

Referring now to FIG. 3, a treated polymer sheet 10 can include an outerperimeter region 22, which is defined as the portion of the sheetlocated within 0.25 inches of the perimeter edges 24 of the sheet 10.Perimeter region 22 is shown as the shaded region of sheet 10 in FIG. 3.The surface may be treated as needed in order to obtain sufficient peeladhesion and, in some embodiments, at least about 5, at least about 10,at least about 15, at least about 20, at least about 25, at least about30, at least about 35, at least about 40, at least about 50, at leastabout 60, at least about 70, at least about 80, or at least about 90percent of the total surface area of perimeter region 22 can be made upof surface-treated locations. In other embodiments, perimeter region 22can be less treated, or may remain untreated, such that, for example,less than about 40, not more than about 30, not more than about 20, notmore than about 10, or not more than about 5 percent of the totalsurface area of the perimeter region 22 is made up of surface-treatedlocations.

As also shown in FIG. 3, the treated sheet 10 can include an interiorregion 26, which includes the surface area of the surface 18 a of sheetoutside 10 of perimeter region 22. According to some embodiments,interior region 26 may also be treated, such that at least about 40, atleast about 50, at least about 60, at least about 70, at least about 80,or at least about 90 percent of the total surface area of interiorregion 26 can be made up of surface-treated locations. In otherembodiments, interior region 26 can be less treated, or may remainuntreated, such that, for example, less than about 40, not more thanabout 30, not more than about 20, not more than about 10, or not morethan about 5 percent of the total surface area of surface region 26 ismade up of surface-treated locations. In some embodiments, only one ofperimeter region 22 and interior region 26 may be treated, while inother embodiments, both may be treated, such that at least about 70, atleast about 80, at least about 90, or at least about 95 percent of thetotal surface area of sheet 10 is made up of surface-treated locations.

The layers and interlayers coated with at least one adhesion stabilizingagent according to various embodiments of the present invention maycomprise one or more thermoplastic polymers. Examples of suitablethermoplastic polymers can include, but are not limited to, poly(vinylacetal) resins, polyurethanes (PU), poly(ethylene-co-vinyl) acetates(EVA), polyvinyl chlorides (PVC), poly(vinylchloride-co-methacrylate),polyethylenes, polyolefins, ethylene acrylate ester copolymers,poly(ethylene-co-butyl acrylate), silicone elastomers, epoxy resins, andacid copolymers such as ethylene/carboxylic acid copoloymers andionomers thereof, derived from any of the previously-listed polymers,and combinations thereof. In some embodiments, the thermoplastic polymercan be selected from the group consisting of poly(vinyl acetal) resins,polyvinyl chloride, and polyurethanes, or the resin can comprise one ormore poly(vinyl acetal) resins. Although described herein with respectto poly(vinyl acetal) resins, it should be understood that one or moreof the above polymer resins could be included with, or in the place of,the poly(vinyl acetal) resins described below in accordance with variousembodiments of the present invention.

Poly(vinyl acetal) resins can be formed by aqueous or solvent-basedacetalization of poly(vinyl alcohol) with one or more aldehydes in thepresence of an acid catalyst. The resulting resin can then be separated,stabilized, and dried according to known methods such as, for example,those described in U.S. Pat. Nos. 2,282,057 and 2,282,026, as well as“Vinyl Acetal Polymers,” in the Encyclopedia of Polymer Science &Technology, 3^(rd) ed., Volume 8, pages 381-399, by B. E. Wade (2003).The total amount of residual aldehyde groups, or residues, present inthe resulting poly(vinyl acetal) resin can be at least about 50, atleast about 60, at least about 70, at least about 75, at least about 80,at least about 85, or at least about 90 weight percent, as measured byASTM 1396. The total amount of aldehyde residues in a poly(vinyl acetal)resin can be collectively referred to as the acetal component, with thebalance of the poly(vinyl acetal) resin comprising residual hydroxyl oracetate groups, which will be discussed in further detail below.

When the poly(vinyl acetal) resin is a poly(vinyl n-butyral) (PVB)resin, greater than 90, at least about 95, at least about 97, or atleast about 99 percent, by weight, of the acetal component, or totalaldehyde residues, can comprise residues of n-butyraldehyde.Additionally, a poly(vinyl n-butyral) resin may comprise less than 10,not more than about 5, not more than about 2, not more than about 1, ornot more than about 0.5 weight percent of residues of an aldehyde otherthan n-butyraldehyde, based on the total weight of aldehyde residues ofthat resin. Examples of poly(vinyl n-butyral) resin include, forexample, BUTVAR® PVB resin, commercially available from Solutia, Inc. (awholly owned subsidiary of Eastman Chemical Company).

In addition to a poly(vinyl acetal) resin, the layers and interlayersmay further include at least one plasticizer. The plasticizer can bepresent in the layer or interlayer in an amount of at least about 5, atleast about 10, at least about 15, at least about 20, at least about 25,at least about 30, at least about 35, at least about 40, at least about45, at least about 50, at least about 55, at least about 60, at leastabout 65, at least about 70 parts per hundred parts of resin (phr)and/or not more than about 120, not more than about 110, not more thanabout 105, not more than about 100, not more than about 95, not morethan about 90, not more than about 85, not more than about 75, not morethan about 70, not more than about 65, not more than about 60, not morethan about 55, not more than about 50, not more than about 45, or notmore than about 40 phr, or in the range of from about 5 to about 120,about 10 to about 110, about 20 to about 90, or about 25 to about 75phr.

As used herein, the term “parts per hundred parts of resin” or “phr”refers to the amount of plasticizer present as compared to one hundredparts of resin, on a weight basis. For example, if 30 grams ofplasticizer were added to 100 grams of a resin, the plasticizer would bepresent in an amount of 30 phr. If the resin composition, layer, orinterlayer includes two or more resins, the weight of plasticizer iscompared to the combined amount of the resins present to determine theparts per hundred resin. Further, when the plasticizer content of alayer or interlayer is provided herein, it is provided with reference tothe amount of plasticizer in the mix or melt that was used to producethe layer or interlayer.

Examples of suitable plasticizers can include, but are not limited to,triethylene glycol di-(2-ethylhexanoate) (“3GEH”), triethylene glycoldi-(2-ethylbutyrate), triethylene glycol diheptanoate, tetraethyleneglycol diheptanoate, tetraethylene glycol di-(2-ethylhexanoate)(“4GEH”), polyethylene glycol bis(2-ethylhexanoate), dipropylene glycoldibenzoate, dihexyl adipate, dioctyl adipate, hexyl cyclohexyladipate,diisononyl adipate, heptylnonyl adipate, di(butoxyethyl) adipate, andbis(2-(2-butoxyethoxy)ethyl) adipate, dibutyl sebacate, dioctylsebacate, and mixtures thereof. The plasticizer may be selected from thegroup consisting of triethylene glycol di-(2-ethylhexanoate),tetraethylene glycol di-(2-ethylhexanoate), and combinations thereof.

In some embodiments, the polymer sheet may include at least oneionomeric resin such as, for example, one or more partially neutralizedacid-ethylene copolymers as mentioned above. In some embodiments,ionomeric resins can include at least about 0.1, at least about 1, atleast about 5, at least about 10, at least about 15 weight percentand/or not more than about 30, not more than about 25, not more thanabout 20 weight percent acid functionality from, for example, one ormore acrylic acids. In some embodiments, the ionomeric resin can have anacid functionality in the range of from 0.1 to 30 weight percent, from 1to 25 weight percent, or from 5 to 20 weight percent, based on the totalweight of the polymer. Examples of suitable acrylic acids can include,but are not limited to, acrylic acid, maleic acid, maleic anhydride,methacrylic acid, itaconic acid, fumaric acid, monomethyl maleic acid,and mixtures thereof. Optionally, the ethylene copolymers may includeone or more additional unsaturated comonomers, including, for example,acrylates and methacrylates such as methyl acrylate, methylmethacrylate, butyl acrylate, butyl methacrylate, glycidyl methacrylate,vinyl acetate, and mixtures thereof. When present, the ethylenecopolymer may include not more than about 50, not more than about 35,not more than about 25, not more than about 15, not more than about 10,not more than about 5 weight percent of one or more additionalunsaturated comonomers.

To form ionomeric resins, acid-functional copolymers may be at leastpartially neutralized with at least one neutralization agent. In someembodiments, the ionomers may be at least about 10, at least about 15,at least about 20, at least about 25, at least about 30, at least about40 percent and/or not more than about 90, not more than about 85, notmore than about 80, not more than about 75 percent neutralized, or thepercent neutralization of the ionomer can be in the range of from 10 to90 percent, from 15 to 85 percent, or from 20 to 80 percent. Examples ofsuitable neutralization agents can include, but are not limited to,metallic ions such as, sodium, potassium, lithium, silver, mercury,zinc, copper, or mixtures thereof, and ammonium ions. The ions may be inmonovalent, divalent, trivalent, or multivalent form. Examples ofcommercially available ionomeric resins can include, for example,Surlyn® resins (commercially available from DuPont). Additionally,ionomeric resin sheets are also commercially available from DuPont,under the trade name Sentryglas® Plus sheets.

Additionally, the layers and interlayers may also include various otheradditives to impart particular properties or features to the interlayer.Such additives can include, but are not limited to, dyes, pigments,stabilizers such as ultraviolet stabilizers, antioxidants, anti-blockingagents, flame retardants, IR absorbers or blockers such as indium tinoxide, antimony tin oxide, lanthanum hexaboride (LaB₆) and cesiumtungsten oxide, processing aides, flow enhancing additives, lubricants,impact modifiers, nucleating agents, thermal stabilizers, UV absorbers,dispersants, surfactants, chelating agents, coupling agents, adhesives,primers, reinforcement additives, and fillers. In some embodiments, thelayers and interlayers may include little or no salts, such as adhesioncontrolling salts (ACAs), such that the layers and interlayers compriseless than about less than about 0.02, less than about 0.01, or less thanabout 0.005 weight percent of one or more salts, including adhesioncontrol salts, based on the total weight of the composition.

In certain embodiments, when the interlayer is a multiple layerinterlayer, one or more of the resin layers can have similarcompositions and can include similar polymer resins and/or may havesimilar types and/or amounts of additives. In some embodiments, two ormore layers of a multiple layer interlayer can have differentcompositions including, for example, different types of polymer resinsand/or different types and/or amounts of additives.

The thickness, or gauge, of each of the layers, or the entireinterlayer, can be at least about 10, at least about 15, at least about20 mils and/or not more than about 100, not more than about 90, not morethan about 60, not more than about 50, or not more than about 35 mils,or it can be in the range of from about 10 to about 100, about 15 toabout 60, or about 20 to about 35 mils. In millimeters, the thickness ofthe polymer layers or interlayers can be at least about 0.25, at leastabout 0.38, at least about 0.51 mm and/or not more than about 2.54, notmore than about 2.29, not more than about 1.52, or not more than about0.89 mm, or in the range of from about 0.25 to about 2.54 mm, about 0.38to about 1.52 mm, or about 0.51 to about 0.89 mm.

In some embodiments, the layers or interlayers can comprise flat polymerlayers having substantially the same thickness along the length, orlongest dimension, and/or width, or second longest dimension, of thesheet, while, in other embodiments, one or more layers of a multilayerinterlayer, for example, can be wedge-shaped or can have a wedge-shapedprofile, such that the thickness of the interlayer changes along thelength and/or width of the sheet, such that one edge of the layer orinterlayer has a thickness greater than the other. When the interlayeris a multilayer interlayer, at least one, at least two, or at leastthree of the layers of the interlayer can be wedge-shaped. When theinterlayer is a monolithic interlayer, the polymer sheet can be flat orwedge shaped. Wedge-shaped interlayers may be useful in, for example,heads-up-display (HUD) panels in automotive and aircraft applications.

According to various embodiments of the present invention, thesurface-treated polymer sheets, including, for example, surface-treatedpoly(vinyl acetal) sheets, may exhibit enhanced adhesion properties ascompared to, for example, similar untreated sheets. In some embodiments,the polymer layers and interlayers that include an adhesion stabilizingagent have higher peel adhesion values than conventional sheets.Additionally, the layers and interlayers according to embodiments of thepresent invention have lower peel adhesion loss and higher adhesionretention, even when exposed to hot and humid conditions.

In some embodiments, layers and interlayers as described herein canexhibit a 90° peel adhesion to glass of at least about 5, at least about5.5, at least about 6, at least about 6.5, at least about 7, at leastabout 7.5, at least about 8, or at least about 8.5 N/cm after exposureto 95% relative humidity at 50° C. for one week.

As a result of the adhesion-stabilizing agent, the sheets and layersdescribed herein may be capable of maintaining adhesion to a substratedespite high levels of moisture ingress, even when the laminate isexposed to conditions of elevated temperature and humidity. For example,the layers and interlayers according to embodiments of the presentinvention may exhibit such a peel adhesion while having an averagemoisture content of at least about 0.4, at least about 0.5, at leastabout 0.7, or at least about 1 percent, measured by Karl-FisherTitration according to ASTM E203.

The 90° peel adhesion to glass values provided herein were determinedaccording to the following procedure. First, a 6.75-inch by 6.75-inchglass/resin/PET laminate was prepared using a nip roll or vacuumde-airing method and the resulting laminate was autoclaved understandard laminated glass production conditions including hold conditionsof 143° C. at 185 psig for 20 minutes. Prior to assembly, the glass waswashed according to standard methods and the resin was conditioned tostandard moisture content of 0.43 weight percent. The PET used in thelaminate had a thickness of 7 mils (178 microns) and had previously beensurface treated in order to provide a minimum 90° peel adhesion to glassof the PET to polyvinyl n-butyral (PVB) of 20 N/cm. Any surfacetreatment method can be used to treat the PET, including, for example,chemical priming, corona treatment, flame treatment, or plasmatreatment, as long as the minimum peel adhesion to PVB is obtained. Whenassembled in the laminate, the surface-treated side of the PET wasoriented toward the layer. The glass used to form the laminates was2.3-mm thick clear float glass, and the laminate was assembled with theair-side surface of the glass oriented toward the layer.

After being autoclaved as described above, the laminates were stored atambient conditions for at least 16 hours prior to exposure. If thelaminates required conditioning prior to adhesion testing, such as, forexample, exposure to high temperature and humidity as discussed infurther detail below, the laminates were placed in a conditioningchamber at the desired temperature and humidity (e.g., 50° C. and 95%relative humidity) for the specified period of time (e.g., 1, 2, or 4weeks). After the exposure period was complete, the conditionedlaminates were removed from the conditioning chamber and allowed to coolto room temperature. Whether conditioned or not, samples were thenprepared for the peel adhesion test by cutting each 6.75-inch by6.75-inch glass laminate into three specimens by first cutting thelaminate into three separate sections, each having dimensions of 2.25inches by 6.75 inches, and then cutting two parallel lines with aspacing of two centimeters down the center of each specimen through thePET and PVB layers along the long side of the specimen. Both cutsextended along the entire length of each specimen. Thereafter, eachspecimen was turned over and the glass was scored and broken along itswidth at a location approximately 2.25 inches from the top. The specimenwas then bent at a 90° angle along the glass score line and a utilityknife was used to cut through the resin and PET layers on either side ofthe 2 cm test strip.

The peel adhesion of each specimen was then testing using a universaltesting machine (UTM), such as those manufactured by Instron or MTSSystems, outfitted with a mounting system designed to perform a 90° peeladhesion measurement. The peel adhesion specimen was held in a slidingmounting device such that the upper 2.25-inch by 2.25-inch section washeld firmly within the grips and the lower 2.25-inch by 4.5-inch sectionwas supported, without interfering with the 2-cm test strip area, andthe sample was oriented so that a 90° was maintained throughout the peeltest. The specimen was then peeled at a rate of 5 inches per minute(in/min). The average peel force required over a length of 3 inches wasdetermined (N) and normalized over the width of the test strip (2 cm) toprovide the 90° peel adhesion value.

The layers and interlayers according to embodiments of the presentinvention also exhibit increased adhesion retention and lower loss ofpeel adhesion, even after exposure to hot, humid conditions. As usedherein, the term “adhesion retention” refers to the amount of adhesion,measured by the 90° peel adhesion to glass test describe above, thatremains after a given time and after exposure to specified conditions.Adhesion retention is calculated using formula (I), below:

$\begin{matrix}{{{{Peel}\mspace{14mu} {Adhesion}\mspace{14mu} {Retention}} = {\frac{{90{^\circ}\mspace{14mu} {Peel}\mspace{14mu} {Adhesion}}_{t}}{{90{^\circ}\mspace{14mu} {Peel}\mspace{14mu} {Adhesion}}_{t = 0}} \times 100}},} & (I)\end{matrix}$

wherein the 90° Peel Adhesion |_(t=0) is the initial 90° peel adhesion,measured prior to any conditioning, and the 90° Peel Adhesion |_(t) isthe final 90° peel adhesion, measured as described above after exposureto 95% relative humidity and a temperature of 50° C. for a time, t. Insome embodiments, t can be 1 week, 2 weeks, or 4 weeks. According tovarious embodiments of the present invention, the layers and interlayersdescribed herein can exhibit a peel adhesion retention, calculatedaccording to formula (I) above, of at least about 25, at least about 30,at least about 35, at least about 40, at least about 45, at least about50, at least about 55, at least about 60, at least about 65, or at leastabout 70 percent, after exposure to 95% relative humidity at 50° C. for1 week or 2 weeks. In some embodiments, the layers and interlayersexhibit a peel adhesion retention of at least about 30, at least about35, at least about 40, at least about 45, at least about 50, at leastabout 55 percent, after exposure to 95% relative humidity at 50° C. for4 weeks.

Similarly, as used herein, the term “loss of peel adhesion” and “peeladhesion loss” refer to the reduction in adhesion, measured by the 90°peel adhesion to glass test described above, exhibited by a given layeror interlayer after a certain period of time and upon exposure tospecified conditions. Loss of adhesion is calculated using formula (II),below:

$\begin{matrix}{{{{Loss}\mspace{14mu} {of}\mspace{14mu} {Peel}\mspace{14mu} {Adhesion}} = {\frac{{90{^\circ}\mspace{14mu} {Peel}\mspace{14mu} {Adhesion}}_{t = 0}{{{- 90}{^\circ}\mspace{14mu} {Peel}\mspace{14mu} {Adhesion}}_{t}}}{{90{^\circ}\mspace{14mu} {Peel}\mspace{14mu} {Adhesion}}_{t = 0}} \times 100}},} & ({II})\end{matrix}$

wherein the 90° Peel Adhesion |_(t=0) is the initial 90° peel adhesion,measured prior to any conditioning, and the 90° Peel Adhesion |_(t) isthe final 90° peel adhesion, measured as described above after exposureto 95% relative humidity and a temperature of 50° C. for a time, t. Aswith the peel adhesion retention, t can be 1 week, 2 weeks, or 4 weeks.The layers and interlayers according to embodiments of the presentinvention can exhibit a loss of peel adhesion of not more than about 60,not more than about 55, not more than about 50, not more than about 45,not more than about 40, not more than about 35, not more than about 30,not more than about 25, or not more than about 15 percent, afterexposure to 95% relative humidity at 50° C. for 1 week or 2 weeks. Insome embodiments, the layers and interlayers can exhibit a loss of peeladhesion of not more than about 60, not more than about 55, not morethan about 50, not more than about 45, not more than about 40 percent,after exposure to 95% relative humidity at 50° C. for 4 weeks.

In some embodiments, the surface-treated polymer sheets of the presentinvention, including, for example, surface-treated ionomeric resinsheets as described herein, may exhibit an average compressive shearadhesion of at least about 20 MPa after exposure to 95% relativehumidity at 50° C. for 3 weeks. This may be comparable to, or higherthan, panels formed with untreated ionomeric resin sheets. In someembodiments, the average compressive shear adhesion of thesurface-treated polymer sheets may be at least about 21, at least about21.5, at least about 22, at least about 22.5, at least about 23, atleast about 23.5, at least about 24, at least about 24.5, at least about25, at least about 25.5 or at least about 26 MPa after exposure to 95%relative humidity at 50° C. for 3 weeks. Additionally, surface-treatedpolymer sheets of the present invention may have a similar averagecompressive shear adhesion values after exposure to 95% relativehumidity at 50° C. for 1 week, as sheets that have had no exposure toconditions of high humidity and high temperature. This consistency ofcompressive shear adhesion performance may indicate that thesurface-treated polymer sheets described herein maintain desirableadhesive properties despite prolonged exposure to high heat and humidityconditions. In some embodiments, the average compressive shear adhesionof a surface-treated polymer sheet exposed to 95% relative humidity at50° C. for 3 weeks can be not more than about 40, not more than about35, not more than about 30, not more than about 25, not more than about20, not more than about 15, or not more than about 10 percent differentthan the average compressive shear adhesion of an identical, butuntreated, resin sheet.

The average compressive shear adhesion values provided herein weredetermined according to the following procedure. First, two sheets of3-mm thick float glass were washed using a standard industrial glasswashing instrument, such as, for example, a Billco Type 210-40-6industrial washer (commercially available from Billco Manufacturing ofZelienople, Pa.). In the washing instrument, the glass was conveyedthrough multiple zones, including a washing zone, a regular water rinsezone, a deionized water rinse zone, and a drying zone, wherein thewashed glass panels are dried with air knives. The liquid used in thewashing zone was prepared by mixing concentrated chlorinated powderedsoap (commercially available from Salute Soap of Tirunelveli, India)with water to form a 0.03 weight percent solution. During the deionizedwater rinse, the temperature of the deionized water was maintained at60.7° C.

After washing, the dried panels were assembled into a glass/polymersheet/glass construct. The resulting construct was then de-aired usingeither a nip roll or a vacuum de-airing method, and the resultinglaminate was autoclaved under standard laminated glass productionconditions that included hold conditions of 143° C. at 185 psig for 20minutes. After being autoclaved, the laminate was drilled to formseveral 3-cm diameter test specimens using a diamond core drill with a3-cm inner diameter (commercially available from Starlight Industries)driven by a drill press rotating at a speed of 430 rpm. The individualtest specimen were either tested as described below, or, optionally,exposed to a set of temperature and humidity conditions for apredetermined amount of time. Once the time period was up, theconditioned samples were tested as described below.

The compressive shear adhesion of a sample was measured by placing thesample into a sample fixture having two independent sections that aredesigned to grip each of the top and bottom glass lites and orient thesample at an angle of 45° to the direction of an applied force. Theforce is created when the two sections of the fixture are moved awayfrom one another at a speed of 3.2 mm per minute. The applied force ismeasured and recorded when the sample ruptures. The compressive shearadhesion (in MPa) is calculated according to the following formula:CSA=F/A, wherein F is the force required to rupture the specimen (inNewtons) and A is the surface area of the sample (e.g., 707 mm² for a3-cm diameter disc). The results of this formula where then converted toMPa by dividing by a conversion factor of 0.70686. The averagecompressive shear adhesion was calculated by averaging the compressiveshear adhesion values for five identical samples prepared andconditioned under the same conditions.

The layers and interlayers described herein may be produced according toany suitable method. The resulting resin composition may be formed intoa sheet or layer according to any suitable method including, but notlimited to, solution casting, compression molding, injection molding,melt extrusion, melt blowing, and combinations thereof. When theinterlayers are multilayer interlayers including two or more sheets,such multilayer interlayers can also be produced according to anysuitable method, including, for example, co-extrusion, blown film, meltblowing, dip coating, solution coating, blade, paddle, air-knife,printing, powder coating, spray coating, and combinations thereof.

In various embodiments of the present invention, the layers orinterlayers may be formed by extrusion or co-extrusion. In an extrusionprocess, one or more thermoplastic polymers, plasticizers, and,optionally, at least one additive, can be pre-mixed and fed into anextrusion device, wherein the layer or interlayer can be melted andextruded from a die to thereby provide an extruded sheet. In someembodiments, multilayer interlayers can be formed by, for example,stacking two or more resin sheets, each having a composition similar toor different than the other resin sheets, and using the stack toassemble a construct for lamination. Accordingly, in these embodiments,the lamination process may be used to create the multiple layerinterlayer while simultaneously forming a multiple layer panel.

According to some embodiments of the present invention, the coatingagent that includes at least one adhesion stabilizing agent, orprecursor thereto, can be applied to one or more surfaces of the polymersheet or interlayer at one or more points during its production. Or, thecoating material can be applied after production, as a post-productiontreatment step. In some embodiments, a method for making a polymer sheetis provided in which at least a portion of the sheet can be coated onduring its production. For example, after the sheet is extruded, orotherwise formed into a resin sheet according to one or more methodslisted above, the coating material may be applied to at least onesurface via dip coating, spray coating, gravure coating, inkjetprinting, or other coating methods. In some embodiments, at least aportion of the sheet may be passed through a bath of coating materialwhile still on the production line. Once coated, the resin can befurther cooled, cut, and removed from the line.

In some embodiments, a method for treating a polymer sheet is providedthat comprises applying a coating material to a pre-formed polymer sheetthat has already been extruded, cooled, and optionally cut to formnon-continuous polymer sheets. Such pre-formed sheets may be, in someembodiments, obtained from a third-party manufacturer or another sourceand may be coated with at least one coating agent according to variousembodiments described above. The pre-formed sheets may be coated andthen stored, or may be coated and then laminated to at least one rigidsubstrate to form a multiple layer panel. The type and amount of thecoating agent used may depend, at least in part, on the size of thesheet and its intended use.

In some embodiments, as discussed above, a coating material thatincludes at least one adhesion stabilizing agent may be applied to atleast a portion of a surface of the resin sheet to thereby provide asurface-treated sheet. As also discussed above, the polymer sheet caninclude any suitable type of polymer, including a poly(vinyl acetal)resin or an ionomeric resin, and the applying may include applying atleast one silanol-containing adhesion stabilizing agent, or precursorthereto, to at least a portion of the surface of the resin sheetaccording to any of the above-described methods. In some embodiments,none, or substantially none, of the coating material or adhesionstabilizing agent may be applied to the surface of the glass. Forexample, less than 10, less than 8, less than 5, less than 2, less than1, or less than 0.5 weight percent of the total amount of adhesionstabilizing agent used in forming a multiple layer panel may be appliedto the surface of one or both substrates.

Once the coating material has been applied to the surface of the polymersheet, and, optionally, permitted to dry, the resulting surface-treatedresin sheet may be assembled between a pair of rigid substrates to forma construct, which can be laminated according to a process that includesat least the following steps: (1) heating the assembly via an IR radiantor convective device for a first, short period of time; (2) passing theassembly into a pressure nip roll for the first de-airing; (3) heatingthe assembly for a short period of time to about 60° C. to about 120° C.to give the assembly enough temporary adhesion to seal the edge of theinterlayer; (4) passing the assembly into a second pressure nip roll tofurther seal the edge of the interlayer and allow further handling; and(5) autoclaving the assembly at temperature between 135° C. and 150° C.and pressures between 150 psig and 200 psig for about 15 to 90 minutes.Other methods for de-airing the interlayer-glass interface, as describedaccording to some embodiments in steps (1) through (4) above includevacuum bag and vacuum ring processes, and both may also be used to formmultiple layer panels using interlayers as described herein.

According to various embodiments of the present invention, the layersand interlayers described herein may be suitable for use in varioustypes of multiple layer panels. Such panels may include a layer orinterlayer and at least one rigid substrate. Any suitable type of rigidsubstrate may be used, including, for example, a substrate made fromglass, polycarbonate, acrylic, metal, ceramic, and combinations thereof.In some embodiments, the multilayer panels may include a pair of rigidsubstrates which sandwich the interlayer therebetween. The multiplelayer panels can be used for a variety of end use applications,including, for example, automotive windshields and windows, aircraftwindshields and windows, structural architectural panels, decorativearchitectural panels, photovoltaic modules, and other similarapplications.

In some embodiments, one or both of the rigid substrates used to form amultiple layer panel may be float glass. Float glass is formed byfloating molten glass on a bed of molten metal to form a uniformlythick, flat glass sheet that has a “tin-side” surface, which was thesurface that formed in contact with the molten metal, and an “air-side”surface, which was the surface that formed away from the molten metal.In some cases, certain polymer sheets may naturally adhere more easilyto the tin-side surface of a sheet of float glass and may have little orno adhesion to the air-side surface. However, in some embodiments,treating such polymer sheets with a coating material including at leastone adhesion stabilizing agent, as described herein, may increase theadhesion of the surface-treated polymer sheet to the air-side surface ofthe glass, even when the resulting panel is subjected to high heat andhumidity conditions as described above. Accordingly, in certainembodiments when at least one of the rigid substrates includes a sheetof float glass, the step of assembling the surface-treated polymer sheetbetween the two rigid substrates to form the construct may includepositioning the surface-treated polymer such that at least a portion ofthe surface-treated locations on the treated surface of the resin sheetare in contact with the air-side surface of the float glass panel.

The following examples are intended to be illustrative of the presentinvention in order to teach one of ordinary skill in the art to make anduse the invention and are not intended to limit the scope of theinvention in any way.

EXAMPLES

Several poly(vinyl acetal) sheets prepared according to embodiments ofthe present invention are provided. More specifically, severalpoly(vinyl acetal) sheets treated with hydrolyzed or unhydrolyzed silanesolutions were prepared and several properties of the treated samples,including 90° peel adhesion, have been determined and are compared withproperties of similar, untreated samples in Examples 1-5, below.Additionally, the adhesive properties of ionomeric resin sheets, treatedaccording to embodiments of the present invention, were also tested, andthe results are provided in Example 6, below.

Example 1: 90° Peel Adhesion of PVB Samples Exposed to Hot, HumidConditions

Two sets of samples of Disclosed Sheets DS-1 and DS-2, each having athickness of about 0.76 mm, were prepared by dip-coating PVB sheets in ahydrolyzed silane solution. The silane solution was formed by addingeither γ-glycidoxypropyltrimethxysilane, commercially available asXIAMETER® OFS 6040 from Dow Corning of Midland, Mich., oraminoethylaminopropyltrimethoxysilane, commercially available asXIAMETER® OFS 6020 from Dow Corning, to deionized water that had beenacidified to a pH of 4 with glacial acetic acid. Silane was added in anamount sufficient to form a 0.4 weight percent solution and the mixturewas stirred for 15 minutes until the solution became clear.

The resin samples were then submerged in the solutions of XIAMETER® OFS6020 (DS-1) or XIAMETER® OFS 6040 (DS-2) for 2 minutes. Aftersubmersion, the samples were air dried and then conditioned at atemperature of 32.7° C. and 24% relative humidity until the moisturecontent of the samples were 0.43 percent. The conditioned samples werethen laminated between a plate of clean soda-lime glass and a 7-milthick, plasma-treated PET film using a nip roll/autoclave technique asdescribed previously. Samples of an untreated Comparative Sheet CS-1,which had not been dipped in a coating solution, were also conditionedand laminated as described above.

An initial value for the 90° peel adhesion to glass of each sample wasdetermined using one sample from each set, and the remaining sampleswere exposed to conditions of 50° C. and 95% relative humidity for aperiod of 2 or 4 weeks. After each conditioning period, one sample fromeach set was removed and the 90° peel adhesion was measured. The resultsof the initial, 2-week, and 4-week 90° peel adhesion tests for each ofthe Comparative and Disclosed Sheets are summarized in Table 1, below.In addition, Table 1 provides the peel adhesion retention and loss ofpeel adhesion for each of the 2-week and 4-week samples, as compared tothe initial 90° peel adhesion values.

TABLE 1 Peel Adhesion of PVB Samples Exposed to Hot, Humid ConditionsPeel Adhesion Loss of Peel Solution Peel Adhesion (N/cm) Retention (%)Adhesion (%) PVB Concentration 2 4 2 4 2 4 Sample Silane (wt %) Initialweeks weeks weeks weeks weeks weeks CS-1 — — 23.77 5.89 6.79 24.8% 28.6%75.2% 71.4% DS-1 XIAMETER ® 0.4 27.70 11.57 13.40 41.8% 48.4% 58.2%51.6% OFS 6020 DS-2 XIAMETER ® 0.4 27.96 14.79 12.96 52.9% 46.4% 47.1%53.6% OFS 6040

As shown in Table 1, above, PVB samples treated with hydrolyzed silaneexhibited higher 90° peel adhesion to glass than untreated PVB, bothinitially and after exposure to hot and humid conditions. Additionally,the Disclosed Sheets DS-1 and DS-2 exhibited higher peel adhesionretention, and a correspondingly lower loss of peel adhesion, thanComparative Sheet CS-1, as shown above.

Example 2: Peel Adhesion of Silane-Treated PVB Samples Treated atVarious Dip Times

Disclosed Sheets DS-3 through DS-5 were prepared by submerging severalsets of PVB sample sheets into an aqueous solution of 0.4 weight percentof XIAMETER® OFS 6040, prepared as described above in Example 1. Eachset of resin samples was submerged and the samples were removed afterdip times of 30 seconds (DS-3), 1 minute (DS-4), and 2 minutes (DS-5).The samples were then air dried, conditioned, and laminated as describedabove. A set of samples of a Comparative Sheet CS-2 was also prepared byconditioning and laminating untreated PVB sheet samples as describedpreviously.

An initial value for the 90° peel adhesion of each sample was determinedusing one sample from each set, and the remaining samples were exposedto conditions of 50° C. and 95% relative humidity for a period of 2weeks. After the conditioning period, the samples were removed and the90° peel adhesion was tested. The results of the initial and 2-week 90°peel adhesion tests for each of the Comparative and Disclosed Sheets aresummarized in Table 2, below. In addition, Table 2 provides the peeladhesion retention and loss of peel adhesion for the samples after 2weeks, as compared to the initial peel adhesion values.

TABLE 2 Peel Adhesion for PVB Samples Treated with Silane at Various DipTimes Peel Loss Solution Peel Adhesion Adhesion of Peel Dip (N/cm)Retention Adhesion PVB Time 2 (%) (%) Sample Silane (min) Initial weeks2 weeks 2 weeks CS-2 — — 17.70 4.40 24.9% 75.1% DS-3 XIAMETER ® 0.522.80 13.00 57.0% 43.0% OFS 6040 DS-4 XIAMETER ® 1 24.50 13.30 54.3%45.7% OFS 6040 DS-5 XIAMETER ® 2 26.20 15.60 59.5% 40.5% OFS 6040

As shown in Table 2, above, the Disclosed Sheet DS-5, which was treatedwith a longer dip time than Disclosed Sheets DS-2 and DS-3, exhibited ahigher initial 90° peel adhesion, as well as a higher 90° peel adhesionafter conditioning in a hot, humid environment. Additionally, each ofthe Disclosed Sheets DS-3 through DS-5 exhibited higher 90° peeladhesion, as well as higher peel adhesion retention (and correspondinglylower loss of 90° peel adhesion) than the untreated sample.

Example 3: Peel Adhesion of PVB Samples Treated with Silane Solutions ofVarying Concentration

Disclosed Sheets DS-6 through DS-9 were prepared by submerging severalsets of PVB sheets into several hydrolyzed silane solutions havingvarying concentrations, including 0.2 weight percent (DS-6), 0.4 weightpercent (DS-7), 0.7 weight percent (DS-8), or 1 weight percent (DS-9) ofXIAMETER® OFS 6040 for a dip time of 2 minutes. After 2 minutes, thesamples were air dried, conditioned, and laminated as described in theabove Examples. Comparative Sheet CS-3 samples were also prepared byconditioning and laminating untreated PVB resin as described previously.

An initial value for the 90° peel adhesion of each sample was determinedusing one sample from each set, and the remaining samples were exposedto conditions of 50° C. and 95% relative humidity for a period of 2weeks. After the conditioning period, the samples were removed and the90° peel adhesion was tested. The results of the initial and 2-week 90°peel adhesion tests for each of the Comparative and Disclosed Sheets aresummarized in Table 3, below. In addition, Table 3 provides the peeladhesion retention and loss of peel adhesion for the samples after 2weeks, as compared to the initial peel adhesion values.

TABLE 3 Peel Adhesion for PVB Samples Treated with Silane of VaryingConcentration Solution Peel Adhesion Peel Adhesion Loss of Peel PVBConcentration (N/cm) Retention (%) Adhesion (%) Sample Silane (wt %)Initial 2 weeks 2 weeks 2 weeks CS-3 — — 23.10 5.20 22.5% 77.5% DS-6XIAMETER ® 0.2 22.80 10.20 44.7% 55.3% OFS 6040 DS-7 XIAMETER ® 0.426.20 15.60 59.5% 40.5% OFS 6040 DS-8 XIAMETER ® 0.7 26.50 15.70 59.2%40.8% OFS 6040 DS-9 XIAMETER ® 1.0 28.10 17.00 60.5% 39.5% OFS 6040

As shown in Table 3, above, Disclosed Sheet DS-9, which was treated witha higher-concentration hydrolyzed silane solution exhibited higher 90°peel adhesion values, both initially and after a 2-week conditioningperiod at high temperature and humidity. Consequently, the peel adhesionretention of DS-9 was higher (and its peel adhesion loss correspondinglylower) than the values for the other sheets. Additionally, as shown inTable 3, each of the Disclosed Sheets DS-6 through DS-9 exhibited higher90° peel adhesion and higher peel adhesion retention than the untreatedComparative Sheet CS-3.

Example 4: Peel Adhesion of Spray-Coated PVB Samples Using Hydrolyzedand Unhydrolyzed Silane Solutions

A hydrolyzed silane solution was formed by adding XIAMETER® OFS 6040 todeionized water that had been acidified to a pH of 4 with glacial aceticacid. The silane was added in an amount sufficient to form a 0.3 weightpercent solution. The surface of several samples of PVB resin were thenevenly spray coated with the hydrolyzed solution. The amount of solutionspray coated onto the surface was dependent on the weight of the sampleand the spray was applied to achieve a target silicon concentration, assummarized in Table 4a, below. Each of the treated Disclosed ResinSheets DS-10 through DS-12 were air dried and laminated as describedpreviously. A set of untreated Comparative Sheet CS-4 samples were alsoprepared by conditioning and laminating untreated PVB resin as describedpreviously.

An initial value for the 90° peel adhesion of each sample was determinedusing one sample from each set, and the remaining sample sets wereexposed to conditions of 50° C. and 95% relative humidity for a periodof 1, 2, and 4 weeks. After a conditioning period, the samples wereremoved and the 90° peel adhesion was tested according to the proceduredescribed previously. The results of the initial, 1-week, 2-week, and4-week 90° peel adhesion tests for each of the Comparative and DisclosedSheets are summarized in Table 4a, below. In addition, Table 4b providesthe peel adhesion retention and loss of peel adhesion for the samplesafter 1, 2, and 4 weeks, as compared to the initial peel adhesionvalues. These values are summarized graphically in FIG. 4.

TABLE 4a Peel Adhesion for PVB Samples Treated with Hydrolyzed SilaneSpray PVB Target Si Peel Adhesion (N/cm) Sample Concentration Initial 1week 2 weeks 4 weeks CS-4 0 36.7 2.6 6.5 10.6 DS-10 5.4 35.1 14.6 12.213.9 DS-11 13 36.1 16.0 17.0 15.2 DS-12 27 34.5 20.7 17.11 15.0

TABLE 4b Peel Adhesion Retention & Loss of Peel Adhesion for PVB SamplesTreated with Hydrolyzed Silane Spray PVB Peel Adhesion Retention (%)Loss of Peel Adhesion (%) Sheet 1 week 2 weeks 4 weeks 1 week 2 weeks 4weeks CS-4 7.1% 17.7% 28.9% 92.9% 82.3% 71.1% DS-10 41.7% 34.8% 39.6%58.3% 65.2% 60.4% DS-11 44.2% 47.1% 42.1% 55.8% 52.9% 57.9% DS-12 60.0%49.6% 43.5% 40.0% 50.4% 56.5%

An unhyrdoylzed silane solution was formed by adding XIAMETER® OFS 6040to methanol to form a 0.3 weight percent solution of silane. The surfaceof several samples of PVB resin were then evenly spray coated with theunhydrolyzed solution. The amount of solution spray coated onto thesurface was dependent on the weight of the sample and the spray wasapplied to achieve a target silicon concentration, as summarized inTable 5a, below. Each of the treated Disclosed Resin Sheets DS-13through DS-15 were then air dried and laminated as described previously.

An initial value for the 90° peel adhesion of each sample was determinedusing one sample from each set, and the remaining sample sets wereexposed to conditions of 50° C. and 95% relative humidity for a periodof 1, 2, and 4 weeks. After a conditioning period, the samples wereremoved and the 90° peel adhesion was tested according to the proceduredescribed previously. The results of the initial, 1-week, 2-week, and4-week 90° peel adhesion tests for each of the Comparative and DisclosedSheets are summarized in Table 5a, below. In addition, Table 5b providesthe peel adhesion retention and loss of peel adhesion for the samplesafter 1, 2, and 4 weeks, as compared to the initial peel adhesionvalues. These values are summarized graphically in FIG. 5.

TABLE 5a Peel Adhesion for PVB Samples Treated with Unhydrolyzed SilaneSpray PVB Target Si Peel Adhesion (N/cm) Sample Concentration Initial 1week 2 weeks 4 weeks CS-4 0 36.7 2.6 6.5 10.6 DS-13 5.4 37.5 3.8 5.311.2 DS-14 13 37.9 5.7 7.4 11.5 DS-15 27 35.0 11.1 12.2 13.7

TABLE 5b Peel Adhesion Retention & Loss of Peel Adhesion for PVB SamplesTreated with Unhydrolyzed Silane Spray PVB Peel Adhesion Retention (%)Loss of Peel Adhesion (%) Sheet 1 week 2 weeks 4 weeks 1 week 2 weeks 4weeks CS-4 7.1% 17.7% 28.9% 92.9% 82.3% 71.1% DS- 10.1% 14.1% 29.9%89.9% 85.9% 70.1% 13 DS- 15.1% 19.5% 30.3% 84.9% 80.5% 69.7% 14 DS-31.8% 34.9% 39.1% 68.2% 65.1% 60.9% 15

Example 5: Peel Adhesion of PVB Sheets with Varying Surface Roughness

Disclosed Sheet DS-16 was prepared by submerging several sets of PVBsheets having a surface roughness, measured by R_(z), of 30 μm into a0.4 weight percent solution of XIAMETER® OFS 6040. After submersion, thesamples were air dried, conditioned, and laminated as described in theabove Examples. Comparative Sheets CS-7 was prepared in a similarmanner, but had an initial surface roughness of less than 4 μm. R_(z)was measured as described previously. Additionally, Comparative SheetsCS-5 and CS-6 were also prepared by conditioning and laminatinguntreated PVB resin as described previously.

An initial value for the 90° peel adhesion of each sample was determinedusing one sample from each set, and the remaining samples were exposedto conditions of 50° C. and 95% relative humidity for a period of 2weeks. After the conditioning period, the samples were removed and the90° peel adhesion was tested. The results of the initial and 2-week 90°peel adhesion tests for each of the Comparative and Disclosed Sheets aresummarized in Table 6, below. In addition, Table 6 provides the peeladhesion retention and loss of peel adhesion for the samples after 2weeks, as compared to the initial peel adhesion values.

TABLE 6 Peel Adhesion Retention & Loss of Peel Adhesion for PVB Sampleswith Varying Surface Roughness Peel Loss of Peel Adhesion Adhesion PeelSilane (N/cm) Retention Adhesion PVB R_(z) Concentration 2 (%) (%)Sample (μm) (wt %) Initial weeks 2 weeks 2 weeks CS-5 30 — 23.1 5.222.5% 77.5% CS-6 <4 — 24.6 4.4 18.0% 82.0% CS-7 <4 0.4 30.0 4.0 13.0%87.0% DS-16 30 0.4 26.2 15.6 59.5% 40.5%

As shown in Table 6, above, when a PVB sheet with a surface roughnessless than 4 μm is treated with hydrolyzed silane solution, a reductionin peel adhesion retention and increased peel adhesion loss is observed,as compared to a PVB sheet having a higher surface roughness treatedunder similar conditions.

Example 6: Average Compressive Shear Adhesion for Ionomeric ResinInterlayers

Sheets of ethylene-carboxylic acid ionomer (commercially available fromDu Pont as Sentryglas® Plus) were used to form severalglass/ionomer/glass constructs using pairs of 3-mm thick sheets of clearfloat glass. Prior to assembling the constructs, each side of one of theionomeric sheets, which measured 6 inches by 6 inches, was spray coatedwith 0.25 mL of a 0.4-weight percent solution formed by addingaminoethylaminopropyltrimethoxysilane, commercially available asXIAMETER® OFS 6020 from Dow Corning, to deionized, water that had beenacidified to a pH of 4 with glacial acetic acid (Solution A). Another ofthe ionomeric sheets was spray coated on both sides with a similar0.4-weight percent solution formed by addingγ-glycidoxypropyltrimethoxysilane, commercially available as XIAMETER®OFS 6040 from Dow Corning, to deionized water that had been acidified toa pH of 4 with glacial acetic acid (Solution B). Both sheets wereallowed to dry before being assembled into a glass/ionomer/glassconstruct with the treated-surfaces of the ionomer resin sheets incontact with the air-side surfaces of each of the glass sheets. Theresulting constructs were de-aired and laminated as described above toform Disclosed Panels DP-1 and DP-2.

Several Comparative Panels were also formed using ionomer resin sheets.Two comparative panels, CP-1 and CP-2, were formed in a similar manneras DP-1 and DP-2, but the air-side surfaces of each glass panel, ratherthan the ionomer, were spray coated with Solution A (Comparative PanelCP-1) or Solution B (Comparative Panel CP-2) and permitted to dry. Theresulting treated glass panels were assembled with the coated surface ofthe glass in contact with the untreated ionomer layers, and theresulting constructs were de-aired and laminated as described above.Similarly, two Control Panels (CoP-1 and CoP-2) were also formed bylaminating an untreated ionomer sheet between untreated float glasspanels, with the float glass oriented with the ionomer in contact withthe air-side (CoP-1) or tin-side (CoP-2) surfaces of the glass panels.Each of Control Panels CoP-1 and CoP-2 were also de-aired and laminatedas described above.

Three sets of 3-cm diameter test specimen were then drilled from each ofDisclosed Panels DP-1 and DP-2, Comparative Panels CP-1 and CP-2, andControl Panels CoP-1 and CoP-2 and the average compressive shearadhesion for each panel was tested for each set of samples as describedabove. An initial average compressive shear adhesion value wasdetermined for one set of samples of each panel, and the remainingspecimen were exposed to conditions of 95% relative humidity and atemperature of 50° C. for 1 or 3 weeks. After the conditioning periodfor each set of samples passed, the specimen were removed and theaverage compressive shear adhesion values of the conditioned specimenwere determined as described above. The results of the initial, 1-week,and 3-week average compressive shear adhesion for each of DisclosedPanels DP-1 and DP2, Comparative Panels CP-1 and CP-2, and ControlPanels CoP-1 and CoP-2 are summarized in Table 7, below.

TABLE 7 Average Compressive Shear Adhesion for Panels formed withIonomeric Resin Interlayers Compressive Shear Adhesion (MPa) CompressiveShear Adhesion (MPa) 1 week at 95% Solution Ionomer Initial¹ RH/50° C.Panel Solution Applied to Contact 1 2 3 4 5 Avg 1 2 3 DP-1 A ResinAir-side 24.3 >28.3 16.4 >28.3 19.5 — >28.3 >28.3 >28.3 DP-2 B ResinAir-side >28.3 >28.3 >28.3 23.4 27.4 — 16.0 19.2 25.2 CP-1 A GlassAir-side >28.3 20.7 15.7 >28.3 21.3 — 24.3 >28.3 >28.3 (Air-side) CP-2 BGlass Air-side 26.9 >28.3 >28.3 25.2 >28.3 — >28.3 22.1 >28.3 (Air-side)CoP- n/a n/a Air-side n/a n/a n/a n/a n/a n/a n/a n/a n/a 1² CoP-2 n/an/a Tin-side 27.6 >28.3 20.2 19.7 26.9 — >28.3 26.5 26.3 CompressiveShear Adhesion (MPa) 1 week at 95% Compressive Shear Adhesion (MPa)RH/50° C. 3 weeks at 95% RH/50° C. Panel 4 5 Avg 1 2 3 4 5 AvgDP-1 >28.3 >28.3 — >28.3 >28.3 >28.3 26 22 — DP-2  21.0 >28.3 — 26 26 2326 13 23 CP-1 >28.3 >28.3 — 26 >28.3 >28.3 >28.3 18 — CP-2 >28.3 >28.3— >28.3 >28.3 >28.3 >28.3 >28.3 — CoP- n/a n/a n/a n/a n/a n/a n/a n/an/a 1² CoP-2  18.9  23.4 — 23 24 24 25 23 24 Notes ¹Equipment had loadcell maximum of 28.3 MPa. Samples that had not ruptured at maximum forcewere removed and reported as having a compressive shear adhesionof >28.3 MPa. ²Untreated air-side samples (COP-1) fell apart duringdrilling and could not be tested.

As shown in Table 7, above, Disclosed Panels DP-1 and DP-2, which wereformed with ionomeric resin layers coated with solutions ofsilane-containing adhesion stabilizing agents, exhibited similarcompressive shear adhesion values as Comparative Panels CP-1 and CP2,which were formed by coating the glass surface. This similarity inadhesion was observed both initially, after no sample conditioning, andafter the samples were exposed to 95% relative humidity at 50° C. for 1and 3 weeks.

While the invention has been disclosed in conjunction with a descriptionof certain embodiments, including those that are currently believed tobe the preferred embodiments, the detailed description is intended to beillustrative and should not be understood to limit the scope of thepresent disclosure. As would be understood by one of ordinary skill inthe art, embodiments other than those described in detail herein areencompassed by the present invention. Modifications and variations ofthe described embodiments may be made without departing from the spiritand scope of the invention.

It will further be understood that any of the ranges, values, orcharacteristics given for any single component of the present disclosurecan be used interchangeably with any ranges, values or characteristicsgiven for any of the other components of the disclosure, wherecompatible, to form an embodiment having defined values for each of thecomponents, as given herein throughout. For example, an interlayer canbe formed comprising poly(vinyl butyral) having a residual hydroxylcontent in any of the ranges given in addition to comprising aplasticizers in any of the ranges given to form many permutations thatare within the scope of the present disclosure, but that would becumbersome to list. Further, ranges provided for a genus or a category,such as phthalates or benzoates, can also be applied to species withinthe genus or members of the category, such as dioctyl terephthalate,unless otherwise noted.

What is claimed is:
 1. A method of making a multiple layer panel, saidmethod comprising: (a) applying a coating material to at least a portionof at least one surface of an ionomeric resin sheet to thereby provide asurface-treated ionomeric resin sheet comprising one or moresurface-treated locations, wherein said coating material comprises atleast one silanol-containing adhesion stabilizing agent or precursorthereto; (b) assembling said surface-treated ionomeric resin sheetbetween a pair of rigid substrates to form a construct, wherein saidsurface-treated ionomeric resin sheet is positioned between said pair ofrigid substrates such that at least a portion of said surface-treatedlocations are in contact with one of said rigid substrates; and (c)laminating said construct to form said multiple layer panel.
 2. Themethod of claim 1, wherein said silanol-containing adhesion stabilizingagent or precursor thereto is present in said coating material in anamount of at least 0.25 weight percent, based on the total weight ofsaid coating material.
 3. The method of claim 2, wherein saidsilanol-containing adhesion stabilizing agent or precursor theretocomprises at least one alkoxysilane selected from the group consistingof γ-glycidoxypropyltrimethoxysilane,aminoethylaminopropyltrimethoxysilane, and combinations thereof.
 4. Themethod of claim 1, wherein at least one of said rigid substratescomprises a float glass panel having a tin-side surface and an air-sidesurface, wherein said assembling includes positioning saidsurface-treated ionomeric resin sheet between said pair of rigidsubstrates such that at least a portion of said surface-treatedlocations are in contact with said air-side surface of said float glasspanel.
 5. The method of claim 1, wherein said applying does not includeapplying said coating material to either of said rigid substrates. 6.The method of claim 1, wherein said applying includes spray coating saidcoating material onto at least a portion of said surface of saidionomeric resin sheet.
 7. The method of claim 1, wherein said coatingmaterial further comprises a carrier liquid and wherein said carrierliquid is water.
 8. The method of claim 1, wherein said surface-treatedionomeric resin sheet exhibits an average compressive shear adhesion ofat least 20 MPa after exposure to 95% relative humidity at 50° C. forthree weeks.